Apparatus for obtaining molten metal sample from metallurgical furnace



Feb. 10, 1970 F. A. MIHALOW ET AL 3,494,200

APPARATUS FOR OBTAINING MOLTEN METAL SAMPLE FROM METALLURGICAL FURNACE Filed Dec. .20, 1967 INV EN TORS MM K. .mJ d w/ mm m United States Patent 3,494,200 APPARATUS FOR OBTAINING MOLTEN METAL SAMPLE FROM METALLURGICAL FURNACE Frederick A. Mihalow, Allentown, Ronald J. Fradeneck,

and Fred A. Achey, Bethlehem, Pa., assignors to Bethlehem Steel Corporation, a corporation of Delaware Filed Dec. 20, 1967, Ser. No. 692,000 Int. Cl. G01n US. Cl. 73425.4 1 Claim ABSTRACT OF THE DISCLOSURE Apparatus suitable to be immersed into a molten ferrous bath to obtain a sample therefrom. The apparatus is an elongated tubular member closed at its upper and lower ends to form a receptacle capable of holding molten metal. An elongated opening in the wall spaced above the lower end allows the molten ferrous metal to flow into the cavity in the elongated tubular member. The elongated opening is provided with a protective cover to prevent slag from entering the receptacle. A deoxidant such as aluminum may be placed in the cavity to deoxidize the sample. The apparatus is attached to rigid means at its upper end by which it may be inserted into the molten ferrous bath.

BACKGROUND OF THE INVENTION In the basic .oxygen process of steelmaking, the shape of the refining vessel and its attendant exhaust system and the violent reactions occurring when oxygen is blown into the charge in the vessel make obtaining samples of the molten metal extremely difficult without interrupting the flow of the gaseous oxygen into the bath. It is the customary practice to interrupt the refining process, withdraw the oxygen lance and tilt the vessel so that a sample of the bath for carbon determination can be obtained with a spoon-type device dipped into the bath. The vessel is then realigned in an upright position, the lance is lowered into the vessel and after the carbon content of the bath has been determined the blowing operation is continued. This process may be repeated several times during the refining of the molten bath until the operator has succeeded in bringing the bath to the proper carbon content.

All of the above steps result in lost production time with an increase in production costs.

Apparatus and techniques have been devised by others to measure the carbon level of the bath by measuring the radiant energy within the furnace or coming off the path or by obtaining a sample of the molten bath using a hollow tube capable of being lowered into and withdrawn from the molten bath. None of these techniques have proven to be reliable for modern steelmaking practices.

SUMMARY OF THE INVENTION It is an object of this invention to provide apparatus for obtaining a solid sample from a molten ferrous bath while the vessel remains in an upright position whereby the content may be accurately determined.

It is still another object of this invention to provide apparatus whereby the loss of a sample of the molten ferrous bath in the vessel is substantially eliminated.

The foregoing objects can be attained by providing an elongated tubular member closed at both ends adapted to be immersed into a molten ferrous bath without danger of losing said member, the receptacle formed by said member having an opening designed to obtain a solid sample. The solidified sample in the elongated tubular member may be cut into appropriate test pieces by conventional means.

3,494,200 Patented Feb. 10, 1970 "ice BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a basic oxygen steelmaking vessel showing the use of the device of this invention.

FIG. 2 is a front elevation view of an embodiment of the device of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a basic oxygen steelmaking vessel 11 holding a molten ferrous metal bath 12 covered by a layer of basic slag 13. The mouth of the vessel is covered by a water cooled hood 14 in which openings are provided for the oxygen lance 15 and an auxiliary lance 16. The auxiliary lance, described in US. Patent No. 3,327,531 to R. Fradeneck, is mounted on a motor driven apparatus capable of raising or lowering it in relationship with the molten bath.

Referring to FIG. 2, an elongated tubular member is shown generally at 17 and includes a metallic outer cylindrical wall 18, closed at its upper end 19 by a steel plug 19a and at its lower end 20 by a steel plug 20a welded thereto to form a hollow receptacle having a cavity 21. A suitable deoxidant for example aluminum wire 21a is placed in the cavity 21. An elongated opening 22 spaced above the lower end 20 is formed in the wall 18 of the e'ongated tubular member 17 to allow the entrance of a small portion of molten ferrous metal from the bath into the hollow receptacle. The elongated opening 22 makes it possible to obtain a dense solid sample of the bath which may be used to determine the carbon content thereof. Samples taken with a sampler having a circular opening are often too porous to be used for carbon determination. The opening 22 is covered with a metallic band 23 for example steel or aluminum which prevents the entrance of slag when the elongated tubular member 17 passes through the slag layer 13 atop the molten ferrous bath 12. The band 23 will melt in the molten bath to allow a portion of the molten metal to flow into the hollow receptacle 21. Attached to the upper end 19 of the elongated tubular member 17 is the lower end 24 of a hollow metalic protective tubular member shown generally at 25. Disposed within the hollow protective tubular member 25 is a rod 26 fixedly attached to the steel plug 19a. The rod 26 extends axially the length of the hollow member 25. The upper end of the rod 26 is attached to a steel plug 27 which has a shoulder 28. The plug 27 rests on the upper end of hollow member 25. A portion of the lower part of the hollow protective tubular member 25 may melt due to the intense heat in the vessel but the rod 26 makes it possible to retrieve the receptacle.

When a sample of the molten ferrous bath is required the oxygen is shut off. The auxiliary lance is lowered into the vesel a distance above the surface of the bath. The apparatus within the auxiliary lance is then pushed downwardly to extend beneath the surface of the molten bath by the device described in US. Patent No. 3,327,531. After a time sufiicient to allow a portion of the molten bath to flow into the hollow receptacle to obtain a sample thereof, the auxiliary lance is raise out of the furnace. The sample of the molten bath solidifies as the apparatus is being removed from the furnace. It is a simple matter to obtain a portion of the sample for chemical analysis by slicing through the elongated tubular member and solidified sample by any conventional means such as a radiac wheel.

It will be understood that the invention is also useful for other steel refining processes such as open hearth and electric furnace processes.

3 4 We claim: ending portion extending over the upper end of said 1. Apparatus for obtaining a sample from a molten metallic tubular members and resting thereon. ferrous bath comprising:

a receptacle having a metallic outer cylindrical wall, References Cited a closed lower end, a closed upper end, a cavity and 5 UNITED STATES PATENTS an opening in the metallic outer cylindrical wall, an elongated rod, one end of which is attached to the upper end of said receptacle and the other end of which is provided with an outwardly extending portion, and a metallic protective tubular member surrounding the 10 LOUIS PRINCE Pnmary Exammer entire body portion of the rod, said outwardly ex- H. C POST Assistant EXamineI 3,295,171 1/1967 Strange et al. 3,298,069 1/1967 Acre. 3,313,159 4/1967 Vanderbeck 73-423 

